1. Field of the Invention
The present invention relates to an air motor, particularly to an air motor used as a power unit for pneumatic tools.
2. Description of the Related Art
An air motor is conventionally used to drive rotational tools such as grinders and drills for grinding and cutting various types of materials because the air motor is suitable for light work and very safe. The air motor includes various types, in which the rotary-vane and turbine types are popular.
In the vane type motor, torque is generated when air pressure works on the adjacent pair of vanes which are radially displacably mounted on a rotor eccentrically installed in a casing.
In the turbine type motor, as already known, torque is generated by blowing air through the turbine.
However, the rotary-vane type motor cannot be made compact or lightweight because it requires many parts and high machining accuracy though it has high efficiency.
Meanwhile, the turbine type motor has the disadvantage that it has inadequate torque and it is difficult to quickly increase the speed decreased through operation and maintain the torque though the structure of the motor is simple and a high speed can be obtained.
That is, these motors have advantages and disadvantages. Therefore, a high-speed type air motor is not yet realized which is compact, lightweight, and which easily generates the required torque.